The present invention relates to a small size multi-way water proof connector with an improved water proof property between a connector housing and a plurality of electric wires connected with terminals, and a method of assembling the same.
A related waterproof connector disclosed in Japanese Patent Publication No. 11-354200A will be explained specifically with reference to FIGS. 8 to 10. A connector housing 11 of a water proof connector 10 comprises a synthetic resin inner housing 12 having a plurality of terminal chambers 13 formed integrally therewith, a synthetic resin outer housing 17 for fitting the inner housing 12 to the inside thereof, and a synthetic resin spacer 28 disposed between the inner housing 12 and the outer housing 17 for holding female terminals 14 accommodated in each terminal chamber 13 of the inner housing 12.
As shown in FIGS. 8 and 9, the inner housing 12 has a box part 12a with the rear side of the upper and lower faces opened, for forming the terminal chambers 13 in a space formed with the center horizontal wall 12b and vertical side walls 12c, serving also as partition walls in the vertical direction. The female terminals 14 can be accommodated in each terminal chamber 13. Moreover, engagement claws 15 are formed integrally, projecting from both sides and the center of the upper and lower faces of the box part 12a as well as flange parts 16 are formed integrally projecting from the front end of the both side center parts. Rectangular insertion holes 12d through which female terminals of a mating connector (not illustrated) are inserted are formed in the front wall of the box part 12a at a position corresponding to each terminal chamber 13. Furthermore, a pair of press-connecting blades 14b are formed by bending each in both side plate parts in the rear part of a box part 14a of the female terminals.
As shown in FIGS. 8 and 9, the outer housing 17 has a double box-like shape with the front side opened, with a substantially quadrilateral pipe-like inner wall part 17a, a substantially quadrilateral pipe-like outer wall part 17b for containing the inner wall part 17a, and a rear wall part 17c, connecting the rear parts of the inner and outer wall parts 17a, 17b. A thick portion is provided in the center of the rear wall part 17c. Rubber plug chambers 19 having a large diameter round cross-section for storing the water proof rubber plugs 18 by press-in are formed at a position corresponding to each terminal chamber 13 at the front side with respect to the thick portion as well as insertion holes 21 having a small diameter round cross-section for inserting electric wires 20 therethrough are formed, communicating with each corresponding rubber plug chamber 19 at the rear side with respect to the thick portion.
Moreover, rectangular engagement holes 22 to be engaged with each engagement claw 15 at both sides of the upper and lower faces of the box part 12a of the inner housing 12 are formed at both front sides of the upper and lower walls of the inner wall part 17a of the outer housing 17 as well as rectangular longitudinal engagement holes 23 to be engaged with each engagement claw 15 at the center of the upper and lower faces of the box part 12a of the inner housing 12 are formed at the front center portion of the upper and lower walls of the inner wall part 17a. Furthermore, a V-shaped receiving groove 25 for receiving an annular rubber water proof packing 24 is formed integrally, projecting from the deep part of the outer face side of the inner wall part 17a of the outer housing 17.
Tapered faces 26 are formed in the front rim of the inner face side of the inner wall part 17a of the outer housing at a position corresponding to each engagement hole 22, 23. Moreover, engagement holes 27 to be engaged with flexible engagement arms of a mating connector (not illustrated) are formed at the front side of the upper and lower walls of the outer wall part 17b of the outer housing 17.
As shown in FIGS. 8 and 9, the spacer 28 forms a box-like shape with the front side opened, with a substantially quadrilateral pipe-like body 28 to be fitted with the inner face side of the inner wall part 17a of the outer housing 17, a substantially quadrilateral pipe-like brim part 28b formed integrally with the front end of the body 28a, bent rearward therefrom, to be fitted with the outer face side of the inner wall part 17a of the outer housing, and a rear wall part 28c of the body 28a.
Accordingly, the box part 12a of the inner housing 12 can be fitted into the body 28a of the spacer 28. Rib-like projections 29 for preventing fall-off of the terminals are formed integrally, projecting from the inner face of the upper and lower walls of the body 28a of the spacer 28, to be engaged with the rear end rim of the box part 14a of the female terminals 14 accommodated in each terminal chamber 13.
Moreover, notch portions 30, 31 are formed in the front side of the portion connecting the body 28a and the brim part 28b of the spacer 28 at a position corresponding to each of the engagement claw 15 and the flange part 16 of the inner housing 12. Engagement claws 32 to be engaged with each engagement hole 23 of the outer housing 17 are formed integrally, projecting form the outer face side of the upper and lower walls of the body 28a of the spacer 28 between the upper and lower side notch portions 30. Furthermore, the tip portion of the brim part 28b can hold the packing 24 engaged with the receiving groove 25 of the inner wall part 17a of the outer housing 17 when the fitting operation with respect to the outer housing 17 is completed.
Moreover, insertion holes 33 are formed in the rear wall part 28c of the spacer 28 at a position corresponding to each insertion hole 21 of the outer housing 17. Furthermore, the rear wall part 28c of the spacer 28 can hold the rubber plugs 18 inserted in each rubber plug chamber 19 of the rear wall part 17c of the outer housing when the fitting operation with respect to the outer housing 17 is completed. As shown in FIG. 8, each electric wire 20 inserted through each insertion hole 21 of the outer housing 17, each rubber plug 18 and each insertion hole 33 of the spacer 28 is press-connected between the pair of the press-connecting blades 14b, 14b of each female terminal accommodated in each terminal chamber 13 of the inner housing 12 so that each terminal chamber 13 and each electric wire 20 are sealed with the rubber plug 18 and the packing 24, respectively.
A conical face (tapered face) 19a is formed at the inlet of each of the rubber plug chambers 19 formed in the rear wall part 17c of the outer housing 17. Conical faces (tapered faces) 28d, each serving also as a rubber compressor, are formed in the outer face of the rear wall part 28c of the spacer 28, and are formed around the wire insertion holes 33, respectively. Before the rubber plugs 18 are inserted respectively into the rubber plug chambers 19 in the outer housing 17 (that is, in a provisional engagement state (FIG. 8) in which the front portion of the body 28a of the spacer 28 is fitted in the inner wall part 17a of the outer housing 17), each rubber plug 18 is held between the conical face 19a of the associated rubber plug chamber 19 and the conical face 28d around the associated wire insertion hole 33 in the spacer 28.
As shown in FIG. 8, conical faces (tapered faces) 18a are formed respectively at the opposite ends of the rubber plug 18 through which the electric wire 20 is passed. The inner diameter Rb of the rubber plug 18 (that is, the diameter of a wire insertion hole 18b in the rubber plug 18) is equal to or larger than the diameter R of the electric wire 20 (Rb.gtoreq.R). The outer diameter Ra of the rubber plug 18 is larger than the diameter D of the rubber plug chamber 19, and the sealing configuration (Ra-Rb+R&gt;D) is established in the rubber plug chamber 19.
The waterproof rubber plug 18 have a substantially cylindrical shape with the rugged inner and outer circumferential faces so that the electric wires 20 can be inserted through the inside thereof without having a gap.
For assembling the waterproof connector 10 of the above construction, the packing 24 is beforehand inserted and set in the receiving groove 25 on the inner wall part 17a of the outer housing 17 (which forms the outer part of the connector housing 11). Then, the electric wires 20 are passed respectively through the plurality of wire insertion holes 21 in the rear wall part 17c of the outer housing 17 from the outside thereof. Then, the electric wires 20 are passed through the rubber plugs 18, respectively, and then are passed respectively through the wire insertion holes 33 in the rear wall part 28c of the spacer 28 from the outside thereof.
Then, as shown in FIG. 6, each rubber plug 18 is not inserted into the associated rubber plug chamber 19 in the rear wall part 17c of the outer housing 17, but the front portion of the body 28a of the spacer 28 is fitted in the inner wall part 17a of the outer housing 17 (that is, disposed in the provisional engagement state), so that each rubber plug 18 is held between the conical face 19a of the associated rubber plug chamber 19 and the conical face 28d around the associated wire insertion hole 33 in the rear wall part 28c of the spacer 28. Then, each electric wire 20 is press-connected to the pairs of press-connecting blades 14b of the female terminal 14 received in the associated terminal chamber 13 in the inner housing 12 (which forms the inner part of the connector housing 11).
Then, the inner housing 12 is fitted into the body 28a of the spacer 28 while sliding the electric wires 20 relative to the wire insertion holes 33 in the rear wall part 28c of the spacer 28 and the wire insertion holes 21 in the rear wall part 17c of the outer housing 17, and the body 28a of the spacer 28 is completely fitted into the inner wall part 17a of the outer housing 17 to be held in a complete engagement state. As a result, the conical face 28d around each wire insertion hole 33 in the rear wall part 28c of the spacer 28 forces the rubber plug 18 into the associated rubber plug chamber 19, thus completing the assembling of the waterproof connector 10 in which the electric wires 20 are sealed by the rubber plugs 18, respectively. During the time when the inner housing 12 is fitted into the spacer 28 fitted in the provisional engagement state in the outer housing 17 through the rubber plugs 18, the insertion of the inner housing 12 is not substantially resisted by the rubber plugs 18, and therefore the waterproof connector 10 can be smoothly assembled without buckling the electric wires 20, and the efficiency of the overall assembling operation is further enhanced.
In the above related waterproof connector 10, as shown in FIG. 6, each electric wire 20 is passed through the rubber plug 18 held in a stand-by state (that is, not yet received in the associated rubber plug chamber 19), and then the distal end portion of the electric wire 20 is press-connected to the female terminal 14 received in the terminal chamber 13 in the inner housing 12, and then the inner housing 12 is inserted and completely retained in the outer housing 17 through the spacer 28 while slidingly moving the electric wires 20 respectively through the wire insertion holes 18b of the rubber plugs 18, so that the rubber plugs 18 are forced into the rubber plug chambers 19, respectively. Thus, the assembling operation is effected while slidingly moving the electric wires 20 relative to the rubber plugs 18, respectively. Therefore, in the case where the number of rubber plugs 18 is large, a total frictional force, produced by the sliding movement of the electric wires 20 relative to the rubber plugs 18, increases, and a load, required for fitting the inner housing 12 into the outer housing 17, increases, which results in a possibility that the production of an electric wire harness is affected. Namely, in the case where the number of rubber plugs 18 is large, the operating load (the rubber plug-inserting load and the housing-fitting load) due to the sliding friction between the rubber plugs 18 and the electric wires 20 increases during the operation for fitting the inner housing 12 into the outer housing 17 through the spacer 28, and this has resulted in a possibility that the efficiency of the assembling operation of the waterproof connector 10 is lowered.
Furthermore, since the rubber plugs 18 are not certainly accommodated in the rubber plug chambers 19 due to the worse efficiency of the assembling operation, the rubber plugs 18 sometimes fall out of the rubber plug chambers 19 after the waterproof connector 11 has been assembled. Under such a circumstance, the waterproof connector does not work because water or the like invades into the connector housing from the portion where the rubber plug has fallen out.